Book = {}
Book_mt = { __index = Book }

function Book.create(self, isbn, title, description, author)
	local attributes = { ISBN = isbn, title = title, description = description, author = author }
    setmetatable( attributes, Book_mt )
    return attributes
end

-- b = Book:create( 1234, 'a', 'b', 'c' )
-- print(b.ISBN)